Patent GB-515229-A (GB)
Title: Improved electron discharge devices of the retarding field type
IPC: H01J25/64
Filed: 1938-05-27
Abstract: 515,229. Electron - discharge apparatus. STANDARD TELEPHONES & CABLES, Ltd. May 27, 1938, Nos. 15931 and 15932. Convention dates, May 29, 1937 and Oct. 2 1937. [Class 39 (i)] In an electron-tube arrangement for genera- . tion, amplification &c., the electrons are caused to move by a magnetic field in a flat spiral of diminishing radius between retarding plates, which are coplanar and are parallel to the plane of the spiral, to supply energy to an output circuit. The electrons may be fired from a gun G, Fig. 1, and trace a spiral path between pairs of semi-circular discs R<1>, R<2>; the pairs are connected together by targets C<1>, C<2> which may be used to limit the path of the electrons. An oscillatory circuit O is connected between the plates. In another form, a hot circular cathode K, Fig. 2, is placed between plates P<1>, P<2> which reflect the electrons so that they can trace a spiral path between the retarding plates R<1>, R<2>. In a further form, an electron beam from a gun G, Fig. 4, is directed tangentially into the space between retarding electrodes T<1>, T<2> which form the pole pieces of the permanent or electro-magnet M and are slit o form an output oscillatory circuit. The length of the slits is equal to a quarter wave length or a whole multiple thereof. Non- magnetic targets C<1> are provided and the electrodes T\ T<2> are coated with silver or copper. The semi-circular discs may be replaced by a number of sectors. In yet another form, filaments 5, Figs. 10, 11, are connected in parallel by supporting discs or rings 8 and are surrounded by a screen 9 connected thereto. Grids or plates 11 are arranged in front of each filament to ensure that electrons arrive at a certain inclination between cylindrical positive electrodes 7. The retarding electrodes are formed by the ends of two pairs of coaxial cylinders 13, 14 and the non-uniform part of the magnetic field of the permanent or electromagnets 17 is used in conjunction with the radial electrostatic field of the electrodes 7 to ensure that the electrons arrive tangentially to the circle which defines the space between the retarding electrodes. An auxiliary magnetic field, the direction of which is opposite to that of the main field, may be provided to deflect the electrons so that they arrive tangentially between the electrodes. As shown in Fig. 14, the main field is produced by electromagnets 17, 18 comprising two pairs of coaxial iron electrodes C, C<1>, and the auxiliary field by an electromagnet comprising iron parts 24, 25, through which pass electrons emitted from an oxide filament 5 and concentrated by a reflector 9. Auxiliary electrodes 7, 7<1> are again provided. In another modification, a cylindrical copper container 2, Fig. 17, is sealed to a glass portion provided with a pinch which supports the electrodes. A circular cathode 5 is mounted within a ring-shaped reflecting iron electrode 9. The auxiliary magnetic field is produced by current in the cathode and electrode 9, and the main field is produced between the two pairs o coaxial electrodes 13, 14. Auxiliary electrodes 7, 7<1> are provided. A coaxial high-frequency transmission line comprises conductors C, 35. The conductor C is screwed into a copper sleeve 37, which surrounds an iron rod 36, carrying the electrode 13, and is secured to a copper sleeve 32, through a glass seal 33. The outer conductor 35 is brazed to the sleeve 32. An iron sleeve 31 supports the electrode 14, and is mounted within a copper sleeve 30 brazed to the jacket 2. Insulating members 38 space the sleeves 32, 37 apart. Curves indicating the electron paths are indicated in the Specification. Specification 488,094 is referred to.